L-Carnitine is a naturally occurring compound that facilitates the transport of fatty acids into the mitochondria for oxidation, and thereby energy production. It is a derivative of the amino acid lysine. Acetyl L-Carnitine (ALCAR) is an acetylated derivative of L-Carnitine.

L-carnitine and its derivatives are used to treat carnitine deficiency, age related decline in mitochondrial function, cardiovascular disease (myocardial infarction, heart failure and angina pectoris), intermittent claudication, end-stage renal failure, Alzheimer's disease, HIV/AIDS and decreased sperm motility. In humans, the endogenous carnitine pool comprises free L-carnitine and a range of short-, medium- and long-chain esterified carnitine derivatives, including acetyl-L-carnitine and propionyl-Lcarnitine, for example. As a supplement taken orally, ALCAR has better bioavailability, than L-carnitine. Therefore, the esterified forms of L-carnitine may be considered as prodrugs of L-carnitine.
Unfortunately, some of the current techniques for administering L-carnitine or its ester prodrugs to patients present several problems. Since L-carnitine and the derivatives ALCAR and propionyl-L-carnitine can cause various side effects such as upset stomach, nausea and vomiting, it is desirable to administer L-carnitine, ALCAR, or propionyl-L-carnitine in a manner that minimizes the manifestation of these side effects. Current administration techniques are hampered in this regard because they present a small therapeutic window between when the benefits of L-carnitine, acetyl-L-carnitine, or propionyl-L-carnitine take effect and when the side effects are manifested.